SCI is known to induce substantial and clinically significant changes in bladder compliance. This is due to significant hypertrophy of the bladder wall, resulting in net tissue stiffening, which in turn results in reduced bladder compliance. In addition to tissue-level changes, it is also recognized that tremendous changes in the shape and thickness occur in the SCI bladder. However, knowledge of alterations in bladder wall morphology with SCI and how these relate to specific tissue mechanical and functional changes in the bladder are presently unknown. Progress has been further hampered by a lack of a basic understanding of the biomechanics of the bladder at the tissue and organ levels, both in health and disease. Since the function of the bladder is to hold large volumes of urine at low pressures and to allow for proper micturition, the need for a thorough understanding of the bladder biomechanics is intuitively obvious. Yet, to date the alterations in bladder shape and wall mechanical properties with SCI bladder are unknown. Further, the link between tissue-level changes and the pressure-volume relationship of the bladder is also unexplored. This is partly due to a lack of multi-axial constitutive (stress-strain) relations for bladder wall and alterations in actual (as opposed to simulated) in vivo bladder geometry. This knowledge is critical for improving our understanding of alterations in bladder function as a result of SCI, as well as providing aid in the establishment of new pharmaceutical agents aimed at treating SCI and related neurogenic disorders. It is hypothesized that SCI induces profound alterations in bladder wall composition and tissue structure, which alter bladder wall mechanical properties. Further hypothesized is that these alterations, in turn, affect bladder function by altering bladder shape. To address these issues, it is proposed to conduct the first integrated biomechanical study of the structure and mechanical properties of the normal and SCI bladder. A key theme wil be to provide the link between alterations in bladder wall tissue morphology with observed changes in tissue mechanical behavior and how these changes are modulated by pharmacological interventions.